Image forming apparatus

ABSTRACT

The present invention provides an image forming apparatus including: a first moving member pressed and moved by an openable/closable member when the openable/closable member is opened, and switching a cartridge from a state where the cartridge is positioned in an image forming position to a state where the positioning is released; and a second moving member pressed and moved by the openable/closable member when the openable/closable member is opened, and moving the exposure member from an exposure position to a retracted position, wherein when the positioning of the cartridge is released, a reaction force applied from the first moving member to the openable/closable member reaches a first peak, when the exposure member is moved to the retracted position, a reaction force applied from the second moving member to the openable/closable member reaches a second peak, and timing of the first peak is different from timing of the second peak.

This application is a continuation of application Ser. No. 13/115,237,filed on May 25, 2011.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electrophotographic image formingapparatus that forms an image on a recording medium in a state where aprocess cartridge including an electrophotographic photosensitive drumand a process unit that acts on the drum is removably mounted to a mainbody of the electrophotographic image forming apparatus.

An electrophotographic image forming apparatus forms an image on arecording medium using an electrophotographic image forming process. Theelectrophotographic image forming apparatus includes, for example, anelectrophotographic copier, an electrophotographic printer (for example,a laser beam printer or an LED printer), a facsimile apparatus, and aword processor. The recording medium includes, for example, paper or anOHT sheet on which an image is formed by the electrophotographic imageforming apparatus.

A process cartridge contributes to an image forming process for formingan image on a recording medium in a state where the cartridge isremovably mounted to a main body of an electrophotographic image formingapparatus. The main body is a component of the electrophotographic imageforming apparatus except the cartridge. The process cartridge includesat least one of a charging unit, a developing unit, and a cleaning unitas process units, and an electrophotographic photosensitive drum onwhich an electrostatic latent image is formed, integrated into acartridge, and is removably mounted to the main body. The process unitacts on the electrophotographic photosensitive drum. Thus, the processcartridge also includes a cartridge including a developing unit as aprocess unit and an electrophotographic photosensitive drum integratedinto the cartridge, and removably mounted to the main body. The processcartridge further includes a cartridge including a charging unit, adeveloping unit or a cleaning unit as a process unit and anelectrophotographic photosensitive drum integrated into the cartridge,and removably mounted to the main body. The process cartridge can bemounted to and removed from the main body by a user. This facilitatesmaintenance of the main body.

2. Description of the Related Art

In an image forming apparatus disclosed in Japanese Patent ApplicationLaid-Open No. H05-035003, an exposure unit is pressed against a part ofan exterior component of a cartridge including a photosensitive drum inconjunction with an opening/closing operation of an exterior cover. Thiscan maintain a certain distance between the exposure unit and thecartridge.

SUMMARY OF THE INVENTION

Japanese Patent Application Laid-Open No. H05-035003 adopts a method ofpressing an exposure unit against a cartridge using a spring, andmaintaining a certain distance between an exposure unit and a cartridge.However, timing of cartridge pressing is the same as timing of exposureunit pressing, and thus a large force is required for closing a cover,and reducing an opening/closing force is desired in terms of usability.

Thus, in the present invention, timing of cartridge pressing is shiftedfrom timing of exposure unit pressing to reduce a force required forpressing.

The present invention provides image forming apparatus in which acartridge that supports a photosensitive member is mounted to an imageforming position, and which forms a latent image on the photosensitivemember by exposure to form an image, including: an exposure member thatincludes a light emitting element arranged in an array, and exposes thephotosensitive member of the cartridge located in the image formingposition in an exposure position; an openable and closable member thatcan be opened or closed with respect to a main body of the apparatus,and can mount the cartridge to the main body of the apparatus in a stateof being opened with respect to the main body of the apparatus; a firstmoving member that is pressed and moved by the openable and closablemember when the openable and closable member is opened, and switches thecartridge from a state where the cartridge is positioned in the imageforming position to a state where the positioning is released; and asecond moving member that is pressed and moved by the openable andclosable member when the openable and closable member is opened, andmoves the exposure member from the exposure position in an arrangementdirection of the cartridge and the exposure member and thus moves theexposure member to a retracted position retracted from the exposureposition, wherein, while the openable and closable member is beingopened, when the first moving member switches the cartridge to the statewhere the positioning is released, a reaction force applied from thefirst moving member to the openable and closable member reaches a firstpeak, and when the second moving member moves the exposure member to theretracted position, a reaction force applied from the second movingmember to the openable and closable member reaches a second peak, andtiming of the first peak is different from timing of the second peak.

The present invention provides an image forming apparatus in which acartridge that supports a photosensitive member is mounted to an imageforming position, and which forms a latent image on the photosensitivemember by exposure to form an image, including: an exposure member thatincludes a light emitting element arranged in an array, and exposes thephotosensitive member of the cartridge located in the image formingposition in an exposure position; an openable and closable member thatcan be opened or closed with respect to a main body of the apparatus,and can mount the cartridge to the main body of the apparatus in a stateof being opened with respect to the main body of the apparatus; a firstmoving member that is pressed and moved by the openable and closablemember when the openable and closable member is closed, and positionsthe cartridge in the image forming position; and a second moving memberthat is pressed and moved by the openable and closable member when theopenable and closable member is closed, and moves the exposure member inan arrangement direction of the cartridge and the exposure member andmoves the exposure member to the exposure position, wherein, while theopenable and closable member is being closed, when the first movingmember positions the cartridge in the image forming position, a reactionforce applied from the first moving member to the openable and closablemember reaches a first peak, and when the second moving member moves theexposure member to the exposure position, a reaction force applied fromthe second moving member to the openable and closable member reaches asecond peak, and timing of the first peak is different from timing ofthe second peak.

The present invention provides an image forming apparatus in which acartridge that supports a photosensitive member is mounted to an imageforming position, and which forms a latent image on the photosensitivemember by exposure to form an image, including: an exposure member thatincludes a plurality of light emitting elements arranged in an array,and exposes the photosensitive member of the cartridge located in theimage forming position by the plurality of light emitting elements in anexposure position; a first moving member that is urged to move thecartridge in a direction different from an insertion direction of thecartridge into the main body of the apparatus when the cartridge ismounted to the main body of the apparatus; and a second moving memberthat is pressed by the cartridge to urge the exposure member and movedto a positioning position to position the exposure member in theexposure position when the cartridge is mounted to the main body of theapparatus, wherein the cartridge is moved by the first moving member andmoved toward the image forming position, while the cartridge is beinginserted into the main body of the apparatus, when the cartridge pressesthe first moving member against a force of urging the first movingmember, a reaction force applied from the first moving member to thecartridge reaches a first peak, and when the cartridge presses thesecond moving member and moves the second moving member to thepositioning position, a reaction force applied from the second movingmember to the cartridge reaches a second peak, and timing of the firstpeak is different from timing of the second peak.

The present invention provides an image forming apparatus in which acartridge that supports a photosensitive member is mounted to an imageforming position, and which forms a latent image on the photosensitivemember by exposure to form an image, including: an exposure member thatincludes a plurality of light emitting elements arranged in an array,and exposes the photosensitive member of the cartridge located in theimage forming position by the plurality of light emitting elements in anexposure position; an openable and closable member that can be opened orclosed with respect to the main body of the apparatus, and can mount thecartridge to the main body of the apparatus in a state of being openedwith respect to the main body of the apparatus; a first moving memberthat is urged to move the cartridge toward the image forming position ina direction different from an insertion direction of the cartridge intothe main body of the apparatus when the cartridge is inserted into themain body of the apparatus; and a second moving member that is pressedby the openable and closable member and urges the exposure member, thesecond moving member moved to a positioning position to position theexposure mechanism in the exposure position, wherein the cartridge to beinserted into the main body of the apparatus presses the first movingmember against a force of urging the first moving member, and is movedtoward the image forming position in the direction different from theinsertion direction of the cartridge into the main body of theapparatus, and when the openable and closable member is closed, theopenable and closable member presses the second moving member and movesthe second moving member to the positioning position.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of an electrophotographic image formingapparatus.

FIG. 1B is a vertical sectional left side view of the apparatus.

FIG. 2A is a partial enlarged view of FIG. 1B.

FIG. 2B is a perspective view of an apparatus in a state where a frontdoor is opened and a top process cartridge is removed or mounted.

FIG. 3A is an appearance perspective view of a cartridge with a drumshutter being opened, seen from the front.

FIG. 3B is an appearance perspective view of the cartridge in FIG. 3Aseen from the back.

FIG. 4A illustrates mounting and removal of the cartridge.

FIG. 4B illustrates positioning of an LED unit.

FIG. 5A illustrates a configuration of a cartridge guide.

FIG. 5B illustrates positioning of the cartridge.

FIG. 6A illustrates an interlocking operation.

FIG. 6B illustrates positioning in a direction perpendicular to aremoval direction of the cartridge.

FIG. 7 illustrates an interlocking mechanism.

FIG. 8 illustrates an interlocking operation of a rod and a cartridgepressing lever.

FIGS. 9A and 9B illustrate a toggle mechanism and an operation thereof.

FIG. 10 illustrates an interlocking mechanism of a door and the rod.

FIG. 11 illustrates a state of the rod and each lever when the door isclosed.

FIG. 12A is a perspective view of the apparatus in a half-open statewith the door being slightly opened.

FIG. 12B is a perspective view of the apparatus in a half-open statewith the door being further opened.

FIG. 13 illustrates a state of the rod and each lever when the door isslightly opened.

FIG. 14 illustrates a state of the rod and each lever when the door isfurther opened.

FIG. 15 illustrates a state of the rod and each lever when the door isopened to an open position.

FIGS. 16A and 16B illustrate a configuration of the electrophotographicimage forming apparatus.

FIG. 17 is an enlarged cross sectional view on a tip side of an LED unitlocated in an exposure position.

FIG. 18 illustrates a toggle mechanism and an operation thereof.

FIG. 19 is a schematic sectional view of a general configuration of theimage forming apparatus.

FIG. 20 is a schematic sectional view of the cartridge and therearoundin the image forming apparatus.

FIG. 21 is a perspective view of the image forming apparatus when thecartridge is mounted, seen obliquely from the front.

FIG. 22 is a schematic perspective view of the cartridge and therearoundin the image forming apparatus.

FIG. 23 is a partial sectional view of the image forming apparatus whenthe cartridge is mounted or removed.

FIG. 24 is a partial sectional view of the image forming apparatus whenthe cartridge is mounted or removed.

FIG. 25 is a partial sectional view of the image forming apparatus whenthe cartridge is mounted or removed.

FIG. 26 is a partial sectional view of the image forming apparatus whenthe cartridge is mounted or removed.

FIG. 27 is a partial sectional view of the image forming apparatus whenthe cartridge is mounted.

FIG. 28A is a graph illustrating an operation force required when thecartridge presses a pull-up member and a push-up member in insertion ofthe cartridge.

FIG. 28B is a graph illustrating an operation force when the cartridgepresses an LED push-up cam in insertion of the cartridge.

FIG. 28C is a graph illustrating an operation force in insertion of thecartridge.

FIG. 29 is a perspective view of the image forming apparatus seenobliquely from the front.

FIG. 30 is a partial sectional view of the image forming apparatus whenthe cartridge is mounted or removed.

FIG. 31 is a partial sectional view of the image forming apparatus whenthe cartridge is mounted.

FIGS. 32A and 32B are perspective views of an inner openable andclosable member and a part of the image forming apparatus around acartridge guide, seen obliquely from above.

FIG. 33 is a sectional view of the cartridge and therearound in theimage forming apparatus seen in an axial direction of a photosensitivedrum.

FIG. 34 is a partial perspective view of the image forming apparatus inwhich the cartridge is placed on a guide member drawn from a main body.

FIG. 35 is a partial sectional view of the image forming apparatus whenthe cartridge is mounted or removed.

FIGS. 36A, 36B, 36C and 36D are partial sectional views of the imageforming apparatus when the cartridge is mounted or removed.

DESCRIPTION OF THE EMBODIMENTS

Preferred embodiments of the present invention will now be described indetail in accordance with the accompanying drawings.

Embodiment 1

{General Configuration of Electrophotographic Image Forming Apparatus}

FIG. 1A is a perspective view of an electrophotographic image formingapparatus 100 according to this embodiment, and FIG. 1B is a verticalleft side view of the apparatus 100. FIG. 2A is a partial enlarged viewof FIG. 1B, and FIG. 2B is a perspective view of the apparatus 100 in astate where a front door is opened and a top process cartridge isremoved or mounted. The apparatus 100 is an in-line colorelectrophotographic image forming apparatus that forms a color image ona recording medium in a state where four process cartridges eachincluding an electrophotographic photosensitive drum are removablymounted to corresponding cartridge mounting portions in a main body. Asan image exposure apparatus (exposure unit) that exposes anelectrophotographic photosensitive drum, an LED unit (a light emittingmember: an LED head array, an LED exposure apparatus) is used. Morespecifically, the apparatus 100 is a four-full-color LED printer usingan electrophotographic process. The apparatus 100 forms a color image ona recording medium S based on electric image information (image signal)input from a host apparatus H such as a personal computer, an imageleader or a counterpart facsimile apparatus to a control circuit portion101.

In the description below, a front side (front face side) of theapparatus 100 is a side into and from which a feed cassette 12 on whichrecording mediums S are stacked and housed is inserted and removed. Arear side (back side) is a side opposite to the insertion and removalside. A lower side is a side on which the feed cassette 12 is provided.Front and rear directions are a direction from the rear side to thefront side of the apparatus (front direction) and a direction oppositethereto (rear direction). Left and right are taken from the front sideof the apparatus. Left and right directions are a direction from rightto left (left direction), and a direction opposite thereto (rightdirection). Top and bottom are taken in a gravity direction. A main body(body) 100A is a component of the apparatus 100 except the processcartridge. A recording medium S includes, for example, paper, an OHTsheet, an envelope, a post card or a label (hereinafter referred to as arecording material) on which an image is formed by the apparatus 100.

In the body 100A, first to fourth cartridge mounting portions 102 (102Y,102M, 102C and 102K) are provided in order from bottom to top in anoblique direction inclined rearward with respect to a verticaldirection. The mounting portions 102 have the same configuration, andeach includes a cartridge guide (cartridge holding member) 71 to which aprocess cartridge P is removably mounted. The guide 71 is secured andprovided on a frame 104 forming a structure of the body 100A. An LEDunit 6 is swingably provided inside the each guide 71. First to fourthprocess cartridges P (PY, PM, PC and PK) containing developers ofdifferent colors are removably mounted to the mounting portions 102. Thefirst cartridge PY is located at a bottom, and the second cartridge PMis located above the first cartridge PY. The third cartridge PC islocated above the second cartridge. Each cartridge P includes anelectrophotographic photosensitive drum 1 and a developing unit 3 forimage visualizing (developing) an electrostatic latent image formed onthe drum 1 with a developer (toner) into a developer image (tonerimage). The cartridges P have the same electrophotographic processmechanism except containing developers of different colors. In thecartridge P in this embodiment, the drum 1, and a charging unit 2, adeveloping unit 3, and a cleaning unit 4 as process units that act onthe drum 1 are integrated into the cartridge in a predetermined relativearrangement in a cartridge frame 5. The drum 1 is rotatably supported bythe frame 5 via a bearing member (not shown). The cartridge P is anassembly with a rotation axis direction of the drum 1 in a longitudinaldirection, one end side of the drum 1 in the rotation axis direction isa drive side, and the other end side is a non-drive side. The chargingunit 2 is a unit that uniformly charges a peripheral surface of the drum1 to predetermined polarity and potential, and a charging roller that isa contact charging member is used as the charging unit 2. The developingunit 3 includes a developing roller 3 a as a developing member forapplying a developer to the drum 1, a feed roller 3 b for feeding thedeveloper to the developing roller 3 a, and a developer containingportion 3 c that contains a powder developer (not shown). The cleaningunit 4 is a unit for removing a transfer residual developer from a drumsurface after a developer image is transferred to the recording materialS, and includes a cleaning blade 4 a as a cleaning member, a wastedeveloper containing portion 4 b, and the like. The first cartridge PYcontains a yellow (Y) developer in the containing portion 3 c, and formsa yellow developer image on a surface of the drum 1. The secondcartridge PM contains a magenta (M) developer in the containing portion3 c, and forms a magenta developer image on the surface of the drum 1.The third cartridge PC contains a cyan (C) developer in the containingportion 3 c, and forms a cyan developer image on the surface of the drum1. The fourth cartridge PK contains a black (K) developer in thecontaining portion 3 c, and forms a black developer image on the surfaceof the drum 1.

In a state where each cartridge P is mounted to a corresponding mountingportion 102 and positioned in a predetermined image forming position Cwith respect to the body 100A, a drive output portion (not shown) of thebody 100A is connected to a drive input portion 59 (FIG. 6B) of thecartridge P. The image forming position C of the cartridge P is aposition for forming an image on the recording material S. A bias outputportion (not shown) of the body 100A is connected to a bias inputportion (not shown) of the cartridge P. An LED unit 6 is positioned inan exposure position D for exposing the drum 1 in a backward of the drum1 with respect to each cartridge P positioned in the image formingposition C. Positioning of the cartridge P and the unit 6 will bedescribed later. FIG. 17 is an enlarged cross sectional view on a tipside of the unit 6 located in the exposure position D. The unit 6 is alight emitting member that is provided in a rotation axis direction(longitudinal direction) of the drum 1, and has a plurality of LEDs(light emitting diodes) 6 a as light emitting elements that emit lightaccording to image information for exposing the drum 1. The unit 6includes an LED substrate 6 b, and a SELFOC™ lens 6 c. The lens 6 c is alens for converging a light emitted from the LED 6 a and exposing thedrum 1. The unit 6 is an exposure unit that selectively controls lightemission of the plurality of LEDs 6 a according to image informationinput from the control circuit portion 101, and performs main scanningexposure of the surface of the rotating drum 1 charged by the chargingroller 2 to form an electrostatic latent image corresponding to theimage information. In the apparatus 100 of this embodiment, the unit 6outputs a light L (LY, LM, LC and LK) modulated according to imageinformation of each of the colors of Y, M, C and K input from a hostapparatus H to the control circuit portion 101 and performs scanningexposure of the drum 1 in the cartridge P of a corresponding color. Theunit 6 as a light emitting member is positioned in the exposure positionD with the cartridge P being positioned in the image forming position C.A plurality of units 6 are arranged in the longitudinal direction of thedrum 1, and include a plurality of light emitting elements that exposeaccording to the image information for exposing the drum 1.

A transfer unit 7 is provided on a front side of first to fourthmounting portions 102 (102Y, 102M, 102C and 102K) to which thecartridges P are removably mounted. The unit 7 includes a driving roller8 and a driven roller 9 provided in upper and lower positions andparallel to each other, an endless conveyor belt 10 looping around therollers 8 and 9, and four transfer rollers (transfer members) 11corresponding to the drum 1 of each cartridge P. The belt 10 is drivenby the driving roller 8, and circulated at a predetermined speed in acounterclockwise direction shown by arrow so as to face and be broughtinto contact with all the drums 1 of the cartridges P mounted to themounting portions 102. With the unit 7 being positioned in apredetermined transfer position H in the body 100A, each roller 11 abutsagainst an inner surface of the belt so as to interpose the belt 10between the roller and the corresponding drum 1 of each cartridge Ppositioned in the image forming position C. In each cartridge P, acontact portion (nip portion) between the drum 1 and the belt 10 is atransfer portion T. The roller 11 is a transfer member for transferring,to the recording material S, a developer image formed on the drum 1using the developing unit 3.

A cassette 12 is provided on a lower side of the body 100A. Sheet-likerecording materials S are stacked in the cassette 12. The cassette 12can be inserted or removed from the front side of the apparatus 100(front loading). Arrows F and G show a drawing direction and aninsertion direction of the cassette 12. For the recording materials S inthe cassette 12, the feed roller 13 is driven to separate and feed onetop recording material S forward in the body 100A in cooperation with aseparation member (not shown). The recording material S is guided upwardby a guide and registered by a pair of registration rollers 14 providedin a downward of the unit 7. A fixing apparatus 15 is provided in anupward of the unit 7. The fixing apparatus 15 fixes an unfixed developerimage formed on the recording material S as a fixed image by applyingheat and pressure. A discharge tray 17 that receives a recordingmaterial on which an image has been formed from a discharge port 16 isprovided on an upper surface of the body 100A.

An operation for forming a full-color image is as described below. Thedrum 1 of each cartridge P is rotationally driven at a predeterminedspeed in a clockwise direction shown by arrow based on an image formingstart signal. The belt 10 is also rotationally driven at a speedcorresponding to the speed of the drum 1 in a counterclockwise directionshown by arrow (forward in drum rotation). The roller 13 is driven toseparate and feed one recording material S from the cassette 12, and therecording material S is registered by the pair of rollers 14 and fed outto a surface of an upward belt portion of the belt 10 from the side ofthe driven roller 9 of the unit 7. The recording material S iselectrostatically adsorbed by a belt surface and conveyed upward bymovement of the belt 10. In each cartridge P, a predetermined chargingbias is applied to the roller 2 at predetermined control timing touniformly charge the surface of the drum to predetermined polarity andpotential. The unit 6 selectively controls light emission of theplurality of LEDs as light emitting elements according to imageinformation input from the control circuit portion 101, and performsmain scanning exposure of the surface of the drum 1 charged by theroller 2. Thus, an electrostatic latent image according to imageinformation of corresponding color is formed on the surface of each drum1. The formed latent image is developed as a developer image by theroller 3 a. A predetermined development bias is applied to the roller 3a at predetermined control timing. By the above operation of theelectrophotographic image forming process, a yellow developer imagecorresponding to a yellow component of a full-color image is formed onthe drum 1 of the first cartridge PY. A magenta developer imagecorresponding to a magenta component of the full-color image is formedon the drum 1 of the second cartridge PM. A cyan developer imagecorresponding to a cyan component of the full-color image is formed onthe drum 1 of the third cartridge PC. A black developer imagecorresponding to a black component of the full-color image is formed onthe drum 1 of the fourth cartridge PK. Specifically, by the operation ofthe predetermined electrophotographic image forming process, thedeveloper images corresponding to the color components of the full-colorimage are formed on the drums 1 of the cartridges P of the respectivecolors. The developer images are electrostatically adsorbed by the belt10 and successively superimposed on and transferred to the surface ofthe recording material S successively passing through transfer portionsT of the cartridges P. A transfer bias of predetermined potential withpolarity opposite to charging polarity of the developer is applied froma power supply portion (not shown) to the roller 11. Thus, unfixeddeveloper images of full-color including four colors: yellow, magenta,cyan and black superimposed are formed on the surface of the recordingmaterial S having fed out of the transfer portion T of the fourthcartridge PK. In each cartridge P, the developer remaining on thesurface of the drum 1 after the transfer is removed by the cleaning unit4. The recording material S fed out of the transfer portion T of thefourth cartridge PK is separated from the surface of the belt 10 by acurvature of the roller 8 and introduced into the fixing apparatus 15,and the unfixed developer image is undergoes fixing treatment on therecording material S. Then, the recording material S is fed out of thefixing apparatus 15 and discharged from the discharge port 16 onto thetray 17 as a full-color image formed material. The unit 7 transfers theimage formed on the drum 1 to the recording material S fed from thelower cassette (feed unit) 12 in the body 100A and conveys the recordingmaterial S upward. After the developer image is fixed on the recordingmaterial S, the recording material S is discharged to the outside of thebody 100A.

{Cartridge}

FIG. 3A is an appearance perspective view of the cartridge P with a drumshutter 52 being opened, seen from the front. FIG. 3B is an appearanceperspective view of the cartridge P seen from the back. On left andright sides of the frame 5, handles 51L and 51R provided to protrude onthe front side of the cartridge, positioned portions 52L and 52R coaxialwith the rotation axis of the drum 1, and insertion guide portions 53Land 53R are symmetrically provided. An exposing groove 55 into which theunit 6 fits is provided on a back side of the cartridge. The exposinggroove 55 with a concave shape is provided in the cartridge P and formsa space through which the light for exposing the photosensitive drum 1passes. The shutter is a member for protecting the drum 1, and can bemanually opened/closed with respect to the frame 5 by an opening/closingmechanism (not shown) in this embodiment. Specifically, the shutter 52can be closed to a closed position (position shown by a dash-double-dotline in FIG. 4A) to hide a drum outer exposure opening window 54 on thefront side of the cartridge, and opened to an opened position (positionshown by a solid line in FIG. 3A) shifted downward from the window 54.When the cartridge P is mounted to the body 100A, the shutter 52 isopened. When the cartridge P is removed from the body 100A, the shutter52 is closed to hide and protect the drum 1. The shutter 52 of eachcartridge P is opened in a state where each cartridge P is mounted to acorresponding mounting portion 102. In a state where a front door(openable and closable member) 31 described later is closed to a closedposition A with respect to the body 100A, the belt 10 of the unit 7positioned in the transfer position H is brought into contact with afront outer exposure portion of the drum 1 of each cartridge P. Theshutter 52 may be automatically opened/closed in conjunction with anopening/closing operation of the door 31. Specifically, when thecartridge P is inserted into the mounting portion 102 and the door 31 isclosed to the closed position A, the shutter 52 is automatically movedfrom the closed position to the opened position by an interlockingmember that interlocks with the closing operation of the door 31. Whenthe door 31 is opened to an opened position B, the shutter 52 can beautomatically moved from the opened position to the closed position.

{Cartridge Replacing Method}

As each cartridge P mounted to the apparatus 100 is used for imageforming, the contained developer (toner) is consumed. Thus, for example,a unit (not shown) for detecting a remaining amount of developer in eachcartridge P is provided, and the control circuit portion 101 compares adetected value of the remaining amount with a preset threshold for alife notice or a life warning of a cartridge. For a cartridge with thedetected value of the remaining amount smaller than the threshold, adisplay portion (not shown) displays a life notice or a life warning ofthe cartridge. This promotes a user to prepare for a replacementcartridge, or promotes the user to replace the cartridge to maintainquality of an output image.

In the apparatus 100 of this embodiment, the cartridge P is replaced bya front access method for improving usability. On the front side of thebody 100A, an opening portion 103 is provided through which eachcartridge P is inserted into and removed from the corresponding mountingportion 102. A front door (front cover: an exterior member of theapparatus 100) 31 is provided as an openable and closable member movablebetween the closed position A for closing the opening portion 103 andthe opened position B (FIG. 2B) for opening the opening portion 103. Inthis embodiment, the door 31 is an operation member operated by the userwhen mounting the cartridge to the body 100A. In this embodiment, thedoor 31 is pivotable around a lower shaft (hinge shaft) 31 b so as to beopened/closed with respect to the body 100A, and can be pivoted to araised direction around the hinge shaft 31 b and closed with respect tothe opening portion 103 as shown in FIGS. 1A and 1B. The door 31 isclosed to close the opening portion 103. The door 31 in the closedposition A is held in the position by a latching mechanism or a togglemechanism (not shown). The door 31 in the closed position A is pivotedaround the shaft 31 b by the user placing his/her fingers on the handle31 a to release the latch or against a toggle force so as tosubstantially horizontally lay the door 31 forward of the main body100A. Thus, as shown in FIG. 2B, the door 31 can be moved to the openedposition B. The door 31 moved to the opened position B is held in theposition. In this embodiment, the unit 7 is opened/closed together withthe door 31 with respect to the opening portion 103 in conjunction withthe opening/closing operation of the door 31. Thus, the door 31 is movedto the opened position B, and thus the front side of each mountingportion 102 is opened, and the front side of the cartridge P mounted toeach mounting portion 102 is exposed to the opening portion 103.

The unit 7 is positioned in the predetermined transfer position H wherethe image can be transferred to the recording material S with respect toeach cartridge P positioned in the image forming position C in a statewhere the door 31 is in the closed position A. When the door 31 in theclosed position A is pivoted in the opening direction around the shaft31 b by releasing the latch or against the toggle force, a door switch(kill switch: not shown) is turned off, and a power supply circuit (notshown) of the apparatus 100 is held in an opened state. In an initialstage of opening pivot of the door 31, an interlocking mechanism (notshown) that interlocks with the opening operation of the door 31releases connection between a drive input portion (not shown) of theunit 7 and a drive output portion (not shown) of the main body 100A.Connection between a drive input portion 59 (FIG. 6B) of the cartridge Pand a drive output portion (not shown) of the main body 100A is alsoreleased. When the door 31 including the unit 7 is opened to the openedposition B, the opening portion 103 of the body 100A is widely opened toprovide accessibility to the mounting portion 102. The door 31 is openedto the opened position B to release positioning of the cartridge P withrespect to the body 100A as described later. Also, the unit 6 is movedfrom the exposure position D (FIG. 2A) for the drum 1 to a retractedposition E (FIG. 4A) and held in the retracted position E. Eachcartridge P mounted to the mounting portion 102 is removed by holdingthe left and right handles 51L and 51R protruding from left and rightsides of the cartridge P to the front side of the cartridge by left andright hands, and drawing the cartridge P forward from the mountingportion 102. Each cartridge P is drawn by sliding the left and rightinsertion guide portions 53L and 53R of the cartridge P in left andright guide groove portions 71 a (FIG. 5A) in the guide 71. By drawingthe cartridge P to move it, the unit 6 is drawn from the exposing groove55, and the cartridge P is removed from the main body 100A. In FIG. 4A,arrow Y shows a removal direction of the cartridge P. The shutter 52 ismanually closed before drawing or after removal of the cartridge P.

The cartridge P is mounted to the mounting portion 102 by holding theleft and right handles 51L and 51R of the cartridge P to hold thecartridge P, and inserting a back side of the cartridge into the guide(body side guide) 71 of the mounting portion 102. This insertion isperformed by respectively engaging the left and right insertion guideportions (cartridge side guides) 53L and 53R of the cartridge P with theleft and right guide groove portions 71 a of the guide 71 and slidingthe guide portions 53L and 53R in the guide groove portions 71 a. InFIG. 4A, arrow X is a mounting direction of the cartridge P. Byinsertion of the cartridge P, the unit 6 located in the retractedposition E fits into the exposing groove 55. Then, when the cartridge Pis sufficiently inserted, the left and right positioned portions 52L and52R are received by the left and right positioning portions 105 (recessin FIG. 5B) of the frame 104 to prevent further insertion. The shutter52 of the cartridge P is manually opened before or after the cartridge Pis inserted into the body 100A.

After the cartridge P is replaced by a new one, the door 31 includingthe unit 7 is pivoted from the opened position B to the closed positionA. By an operation of an interlocking member 80 (FIG. 6A) describedlater interlocking with the closing operation of the door 31, eachcartridge P is positioned with respect to the frame 104. The positioningposition is the image forming position C of the cartridge P. The unit 6is moved from the retracted position E to the exposure position D andpositioned with respect to the cartridge P positioned in the imageforming position C. The unit 7 is positioned in the transfer position Hwith respect to the body 100A. Specifically, the belt 10 of the unit 7is brought into contact with an exposed portion outside the front of thedrum 1 of each cartridge P positioned in the image forming position C.The door 31 closed to the closed position A is held in the position by alatching mechanism or a toggle mechanism (not shown). In this state, thedoor switch is turned on, and the power supply circuit of the apparatus100 is held in a closed state. The drive output portion of the main bodyis connected to the drive input portion 59 of the cartridge P. A biasoutput portion of the main body 100A is connected to a bias inputportion of the cartridge P. The drive output portion of the main body isconnected to the drive input portion of the unit 7. The bias outputportion of the main body 100A is connected to the bias input portion ofthe unit 7. In this state, the apparatus 100 can perform an imageforming operation.

{Positioning Configuration of Cartridge P and Unit 6}

The unit 6 is supported by a support member (light emitting membersupport) 61. The guide 71 includes shaft portions 72 respectivelyprotruding in a cartridge removal direction Y at left and right portionsinside a rear plate. Guide holes 62 on left and right sides of thesupport 61 fit on the left and right shaft portions 72. Thus, thesupport 61 is supported by the guide 71 so as to be movable (swingable)along the shaft portion 72 in the cartridge insertion direction X andthe cartridge removal direction Y opposite thereto in the guide 71. Acoil spring (biasing member or elastic member) 73 is externally fittedto a base of the shaft portion 72 between the support 61 and the guide71. The support 61 is moved by a predetermined amount in the cartridgeremoval direction Y by a biasing force (elastic force) of the spring 73in a free state. With this configuration, the unit 6 is supported by thesupport 61 so as to be located in the exposure position D where thelight emitting element emits light to expose the drum 1, and theretracted position E where the unit 6 is retracted from the exposureposition D. In a state where the cartridge P is positioned in the imageforming position C, the position in the cartridge removal direction X inthe exposure position D of the unit 6 is determined as described below.Specifically, the position is determined by the support 61 abuttingagainst a drum cover 56 that positions the drum 1 as shown in FIG. 4B bya biasing force of the spring 73. The direction perpendicular to thecartridge removal direction X of the unit 6 and the axial direction ofthe drum 1 are determined by engagement between the guide hole 62 andthe shaft portion 72. The support 61 includes protrusions 63 (63Y, 63M,63C and 63K) extending to the outside of the body frame 104 as shown inFIG. 7. The protrusion 63 is pressed in the cartridge insertiondirection X by a rotatable lever 91 (91Y, 91M, 91C and 91K) against thebiasing force of the spring 73. Thus, the support 61 is moved inward(rearward) of the body and retracted away from the drum cover 56.Specifically, the unit 6 is moved from the exposure position D to theretracted position E and held in the retracted position E. The lever 91is away from the protrusion 63 in a state where the apparatus 100 canperform an image forming operation. At that time, as shown in FIG. 6A,the lever 91 is urged in the arrow direction (clockwise direction) by anelastic force of the spring (elastic member) 20 and abuts against theshaft 21 embedded in the frame 104. In this state, the support 61 ismoved in the cartridge removal direction Y by a biasing force of thespring 73, and the support 61 abuts against the drum cover 56. Thus, theunit 6 is moved from the retracted position E to the exposure position Dand positioned in the exposure position D (FIG. 4B).

The lever 91 is a light emitting member positioning member (lightemitting member pressing member) for positioning (pressing) the support61 so that the unit 6 is positioned in the exposure position D. Thelever 91 is moved between a positioning position (pressing position forpressing) Q where the support 61 is pressed and positioned so that theunit 6 is positioned in the exposure position D and a retracted positionR where the lever 91 is retracted from the positioning position Q. A rod(interlocking member) 80 slidable in an upward direction shown by arrowJ and a downward direction shown by arrow K opposite to the upwarddirection is placed outside the frame 104. The rod 80 is verticallymoved in conjunction with the opening/closing operation of the door 31as described later. The vertical movement of the rod 80 performspressing release and pressing of the protrusion 63 by the lever 91.Specifically, the unit 6 is moved between the exposure position D andthe retracted position E.

Next, positioning of the cartridge P will be described. The position ofthe cartridge P in the insertion direction X is determined by the leftand right positioned portions 52L and 52R being received by the left andright positioning portions 105 of the frame 104 as shown in FIG. 5B. Theposition of the cartridge P in the removal direction Y is determined bya projection 57 of the drum cover 56 being pressed by a biasing force ofa pivotable cartridge pressing lever 120 placed on the frame 104. Thelever 120 is a cartridge positioning member (cartridge pressing memberfor pressing the cartridge P in the image forming position C) forpositioning the cartridge P in the image forming position C. By thepressing, the positioned portions 52L and 52R of the cartridge P arepressed against the positioning portion 105 and the cartridge P ispositioned and held in the image forming position C. The directionperpendicular to the removal direction Y of the cartridge P isdetermined as shown in FIG. 6B. Specifically, the direction isdetermined in such a manner that the cartridge P is rotated around thedrive input portion 59 by a rotation drive force input from the driveoutput portion (not shown) to the drive input portion of the cartridgeP, and the protrusion 58 of the cartridge P abuts against the abutmentsurface 106 of the frame 104.

Pressing and pressing release of the cartridge P by the lever 120 arealso performed in conjunction with sliding of the rod 80 like pressingand pressing release of the unit 6. As shown in FIG. 8, the rod 80 isslid downward shown by arrow K, and thus a cartridge pressing abutmentportion 80 b on a back surface (body inner surface) of the rod 80 abutsagainst an upper surface of the protrusion 120 a of the lever 120. Thus,the lever 120 is pivoted in a direction away from the projection 57 ofthe cartridge P. Specifically, the lever 120 is moved from thepositioning position (pressing position for pressing) M where thecartridge P is pressed and positioned in the image forming position C tothe retracted position N where the cartridge P is retracted, andpressing of the positioned portions 52L and 52R of the cartridge Pagainst the positioning portion 105 is released. On the other hand, therod 80 is slid upward shown by arrow J, the abutment portion 80 b of therod 80 abuts against the lower surface of the protrusion 120 a of thelever 120 to press the lever 120. Thus, the lever 120 is pivoted in thedirection toward the projection 57 of the cartridge P, and thepositioned portions 52L and 52R of the cartridge P are pressed againstthe positioning portion 105. Specifically, the lever 120 is moved fromthe retracted position N to the positioning position M where thecartridge P is pressed and positioned in the image forming position C,and the positioned portions 52L and 52R of the cartridge P are pressedagainst the positioning portion 105. As shown in FIG. 9A, the lever 91is urged in the clockwise direction by a lever spring (elastic member)93 (toggle mechanism), and the lever 120 is urged in thecounterclockwise direction by a pressing lever spring (elastic member)121 (toggle mechanism). When the levers are pivoted by a certain angleor more, as shown in FIG. 9B, the urging directions are changed by thetoggle mechanisms. Specifically, the lever 91 and the lever 120 areurged (pressed) by the toggle mechanisms 93 and 121.

An interlocking mechanism between the door 31 and the rod 80 will bedescribed. As shown in FIG. 10, the door 31 includes a door gear 23concentric with the lateral shaft 31 b (FIG. 1B) as a center ofopening/closing. The gear 23 is rotated around the lateral shaft 31 bintegrally with the door 31 along with the opening/closing operation ofthe door 31. An intermediate link gear 25 meshes with the door 31 via anidler gear 24. An intermediate link 26 is provided concentricallyintegrally with the gear 25. The link 26 engages a door link arm 27. Thegear 24, the gear 25, the link 26 and the arm 27 are pivotally supportedon the frame 104. In conjunction with the opening operation of the door31 from the closed position A to the opened position B, the gear 23 isrotated in the counterclockwise direction shown by arrow, the gear 24 isrotated in the clockwise direction shown by arrow, the gear and the link26 are rotated in the counterclockwise direction shown by arrow, and thelever 27 is rotated in the clockwise direction shown by arrow. The arm27 has a shape to press the protrusion 81 of the rod 80, and the rod 80is slid downward shown by arrow K by an amount according to the rotationangle of the arm 27. In reverse, the rod 80 is slid upward inconjunction with the closing operation of the door 31.

The operation of releasing pressing of the cartridge P and the operationof retraction of the unit 6 in conjunction with the opening operation ofthe door 31 by the user and operation timings thereof will be described.The door 31 is closed in a printable state of the apparatus 100 (FIGS.1A and 1B). In this state, as shown in FIG. 11, a protrusion 92 of thelever 91 is away from the pressure release abutment portion 80 a, andthe abutment portion 80 b is away from the protrusion 120 a of the lever120. In this state, the cartridge P is pressed by the lever 120 andpositioned and held in the image forming position C. The unit 6 ispressed against the cartridge P positioned in the image forming positionC by the biasing force of the spring 73 and positioned in the exposureposition D.

When the user opens the door 31 for cartridge replacement or jamtreatment, a latch (not shown) of the door 31 engaging a member (notshown) provided on the body 100A is released, and the door 31 can beturned to the opened position B. FIG. 12A illustrates a half-open statewith the door 31 slightly opened, and FIG. 12B illustrates a half-openstate with the door 31 further opened. When the door 31 is pivoted fromthe state in FIG. 12A, as described above, the rod 80 is slid downwardshown by arrow K. When the door 31 is pivoted by a certain angle, asshown in FIG. 13, the abutment portion 80 a of the rod 80 abuts againstand presses the protrusion 92 of the lever 91, and the retractionoperation of the unit 6 is completed. The unit 6 is held by the togglemechanism 93 with pressing being released by the spring urging directionbeing changed from that in FIG. 9A to that in FIG. 9B. At this time, thelever 120 has not yet been pivoted as shown in FIG. 13. Specifically,the lever 120 is positioned in the positioning position M where thecartridge P is positioned in the image forming position C. Further, whenthe rod 80 is slid downward, as shown in FIG. 14, the abutment portion80 b abuts against and presses the protrusion 120 a to release pressingof the cartridge P. When the rod 80 is further slid downward, as shownin FIG. 15, the lever 120 is retracted from a cartridge removal path.The lever 120 is held by the toggle mechanism 121 with pressing beingreleased by the spring urging direction being changed from that in FIG.9A to that in FIG. 9B. Specifically, the lever 120 is moved from thepositioning position M to the retracted position N. The door 31including the unit 7 is moved to the opened position B to widely openthe opening portion 103, and each cartridge P is exposed from theopening portion 103 and can be removed to the outside of the body 100A.

An operation will be described when the door 31 including the unit 7 isclosed after the cartridge replacement or the jam treatment is finished.With the door 31 being opened, the protrusion 92 of the lever 91 abutsagainst the abutment portion 80 a of the rod 80, and the abutmentportion 80 b of the rod 80 abuts against the protrusion 120 a of thelever 120 (FIG. 15). In this state, pressing of both the cartridge P andthe unit 6 is released (positioning release). When the door 31 isclosed, the rod 80 is slid upward shown by arrow J (FIG. 8) inconjunction with the closing operation as described above. When the door31 is pivoted by a certain angle, the abutment portion 80 b of the rod80 is moved away from the protrusion 120 a of the lever 120 from FIG. 14to FIG. 13 and the cartridge pressing operation is completed.Specifically, the lever 120 is moved from the retracted position N tothe positioning position M. At this time, the lever 91 has not yet beenpivoted. Specifically, the lever 91 is positioned in the retractedposition R. When the door 31 is closed and the rod 80 is further slidupward, the abutment portion 80 a is moved away from the protrusion 92,and the unit 6 abuts against the cartridge cover 56. Specifically, thecartridge P is positioned in the image forming position C, and the unit6 is pressed against the drum cover 57 of the cartridge P and positionedin the exposure position D. Then, the apparatus 100 enters a printablestate with the door 31 being sufficiently closed.

In the above, the rod 80 is the interlocking member that moves the lever120 from the retracted position N to the positioning position M inconjunction with the operation of the door 31 (operation member,exterior member) to mount the cartridge P to the body 100A. The rod isalso the interlocking member that then moves the lever 91 from theretracted position R to the positioning position Q so that the unit 6 ispositioned from the retracted position E to the exposure position D. Therod 80 is the interlocking member that retracts the lever 91 from thepositioning position Q to the retracted position R so that the unit 6 isretracted from the exposure position D to the retracted position E inconjunction with the operation of the door 31 to remove the cartridge Pfrom the body 100A. The rod 80 is the interlocking member that thenretracts the lever 120 from the positioning position M to the retractedposition E.

In the configuration of this embodiment, when the door 31 is opened, areaction force is applied from the lever 91 and the lever 120 of thetoggle mechanism via the rod 80 to the door 31 in the retractionoperation of the unit 6 from the exposure position D to the retractedposition E and the positioning release operation of the cartridge P fromthe image forming position C. From the property of the toggle mechanism,the reaction force reaches a peak immediately before an urging directionof a spring (lever spring 93, pressing lever spring 121) of the togglemechanism changes.

In this embodiment, when the door 31 is opened, the retraction operationof the unit 6 from the exposure position D to the retracted position Eis first performed. Then, the pressing release operation of thecartridge P, that is, the positioning release operation of the cartridgeP from the image forming position C is performed. When the door 31 isclosed, the pressing operation of the cartridge P, that is, thepositioning operation of the cartridge P in the image forming position Cis performed. Then, the pressing operation of the unit 6 from theretracted position E to the exposure position D is performed. Thus, thepressing state and the pressing release state are switched using thetoggle mechanism to change the pressing timings. This requires a smalleropening/closing force of the door 31 as compared to the case ofsimultaneous pressing. Specifically, the pressing timings are changed,and thus reactions force applied from the lever 91 and the lever 120 ofthe toggle mechanism via the rod 80 to the door 31 reach the peak atdifferent timings. This reduces a maximum value of an operation forcerequired for opening/closing the door 31 as compared to a case ofsimultaneously reaching the peak, thereby improving usability.

As shown in FIG. 6A, in this embodiment, when the door 31 is closed, thelever 91 is moved in the Q direction by the elastic force of the spring20 and moved from the retracted position R to the positioning positionQ. However, the lever 91 may be moved in the Q direction and moved fromthe retracted position R to the positioning position Q and held in thepositioning position Q using the lever spring 93 (FIGS. 9A and 9B) asthe toggle mechanism rather than the elastic force of the spring 20. Inthis case, as shown in FIG. 18, the rod 80 includes the abutment portion80 c that abuts against and presses the lever 91 in the J direction whenthe rod 80 is moved in the J direction. Then, the abutment portion 80 cof the rod 80 may pivot the lever 91 in the Q direction from the statewhere the lever 91 is urged in the R direction by the lever spring 93 tothe state where the lever 91 is urged in the Q direction by the leverspring 93.

In this configuration, when the door 31 is closed, the rod 80 is movedin the J direction and abuts against and presses the lever 120, andperforms the positioning operation of the cartridge P in the imageforming position C. Then, the abutment portion 80 c of the rod 80 abutsagainst and presses the lever 91, and performs the pressing operation ofthe unit 6 from the retracted position E to the exposure position D.

When the door 31 is closed, as when the door 31 is opened, the reactionforce is applied from the lever 91 and the lever 120 of the togglemechanism via the rod 80 to the door 31, and the reaction force reachesthe peak immediately before change of the urging direction of the spring(lever spring 93, press lever spring 121) of the toggle mechanism.

In contrast to this, in order to change the pressing timings of thelever 120 and the lever 91, the reactions force applied from the lever91 and the lever 120 of the toggle mechanism via the rod 80 to the door31 reaches the peak at different timings. This reduces a maximum valueof an operation force required for opening/closing the door 31 ascompared to the case of simultaneously reaching the peak, therebyimproving usability.

Embodiment 2

FIGS. 16A and 16B illustrate an image forming apparatus 100 of thisembodiment. The apparatus 100 of this embodiment includes an inner cover7A (double-sided unit) that also serves to perform double sidedconveyance between a door 31 and a transfer unit 7 in the apparatus 100of Embodiment 1 to enable execution of double-sided printing. The door31, the inner cover 7A and the transfer unit 7 are individuallypivotable around a lower hinge shaft portion (not shown) so as to beopened/closed with respect to a body 100A. A link lever 41 fortransmitting pivot of the unit 7A to the rod 80 is placed on a rotationcenter of the unit 7A. The lever 41 is pivoted in a counterclockwisedirection shown by arrow by opening pivot of the unit 7A. The lever 41includes a protrusion 41 a, and the protrusion 41 a presses a protrusion42 a of an intermediate link 42 to pivot the link 42 in a clockwisedirection shown by arrow, and a rod pressing portion 42 b of the link 42presses a rod protrusion 81. Thus, the rod 80 is slid downward shown byarrow K. By the closing pivot of the unit 7A, the lever 41, the link 42and the rod 80 perform operations opposite to those in the opening pivotof the unit 7A. In this embodiment, the door 31, the inner cover 7A andthe transfer unit 7 are operation members operated when the user mountsa cartridge to the body 100A. In this embodiment, by vertical sliding ofthe rod 80 with the opening/closing operation of the inner cover 7A inconjunction with the operation of the inner cover 7A, cartridge pressingand pressing release, LED unit pressing and retraction operation areperformed as in Embodiment 1. In removal of the cartridge P, the door 31is pivoted to be opened, and then the inner cover 7A is pivoted to beopened. By downward sliding of the rod 80 that interlocks with the innercover 7A with the opening pivot, the retraction operation of the unit 6and the pressing release of the cartridge P are performed. Then, theunit 7 is pivoted to be opened to remove the cartridge P from theopening portion 103. When the cartridge P is replaced by a new one, theunit 7 is pivoted to be closed, and then the inner cover 7A is pivotedto be closed. By upward sliding of the rod 80 that interlocks with theinner cover 7A with the closing/opening pivot, the pressing operation ofthe cartridge P and the pressing operation of the unit 6 are performed.The door 31 is finally closed.

In this embodiment, when the inner cover 7A is opened, the retractionoperation (movement from an exposure position D to a retracted positionE) of the unit 6 is first performed, and then the pressing releaseoperation (positioning releasing from an image forming position C) ofthe cartridge P is performed. When the inner cover 7A is closed, thepressing operation (positioning in the image forming position C) of thecartridge P is first performed, and then the pressing operation(movement from the retracted position E to the exposure position D) ofthe unit 6 is performed. The pressing state and the pressing releasestate are switched by a toggle mechanism as in Embodiment 1, andpressing timings are changed (made different). This requires a smalleropening/closing force of the inner cover 7A as an operation member ascompared to a case of simultaneous pressing.

Other Matters

The image forming apparatuses of Embodiments 1 and 2 are examples of anin-line color printer, but the same advantage can be obtained for aconfiguration of a black-and-white printer.

As a light emitting element of the light emitting member 6, for example,a field light emitting element such as a liquid crystal element, asemiconductor light emitting diode or an organic electroluminescenceelement (organic EL element) is used. The semiconductor light emittingdiode is a semiconductor device that emits light in application of avoltage. The organic EL element is an electronic material made of anorganic compound that shines in application of a voltage, and emitslight by itself. For example, in the organic EL element, an organicmolecule light emitting layer is interposed between two electrodes toapply a voltage. Thus, an electron injected from the electrodes and ahole are recombined to excite an organic molecule, and light is emittedwhen the excited organic molecule returns to a base state.

In the present invention, the operation members operated by the userwhen the cartridge P is mounted to the main body 100A are not limited tothe front door 31 in Embodiment 1 and the double-sided unit 7A inEmbodiment 2. For example, the operation member such as a lever may beused.

In Embodiments 1 and 2, the cartridge P is positioned in the imageforming position C by pressing, but may be positioned by pulling thecartridge P. In Embodiments 1 and 2, the unit 6 as the light emittingmember is positioned in the exposure position D by pressing the support61, but may be positioned by pulling the support 61.

In Embodiments 1 and 2, the unit 6 is positioned in the exposureposition D by the support 61 abutting against the drum cover 56.However, a positioning portion may be formed on the frame 104, and theunit 6 may be positioned in the exposure position D by the support 61abutting against the positioning portion of the frame 104 like thecartridge P.

In such a positioning configuration, when the door 31 or the inner coverA is opened, the pressing release operation of the cartridge P, that is,the positioning release operation of the cartridge P from the imageforming position C is first performed. Then, the retraction operation ofthe unit 6 from the exposure position D to the retracted position E isperformed. Such a configuration may be allowed.

When the door 31 or the inner cover A is closed, the pressing operationof the unit 6 from the retracted position E to the exposure position Dis first performed. Then, the pressing operation of the cartridge P,that is, the positioning operation of the cartridge P in the imageforming position C is performed. Such a configuration may be allowed.

With such a configuration, as in the above-described embodiments,pressing timings of the cartridge P and the unit 6 are changed (madedifferent), and thus reaction forces applied from the lever 91 and thelever 121 to the door 31 or the inner cover 7A reach the peak atdifferent timings. This requires a smaller opening/closing force ascompared to the case of simultaneous pressing.

In Embodiments 1 and 2, when the door 31 or the inner cover A is openedand closed, the pressing timings of the cartridge P and the unit 6 arechanged (made different). However, the pressing timings of the cartridgeP and the unit 6 may be changed (made different) either when the door 31or the inner cover A is opened or when closed. This also requires asmaller opening/closing force of the door 31 as compared to the case ofsimultaneous pressing when the door 31 or the inner cover A is opened orclosed.

The above descriptions are on Embodiments 1 and 2, and Embodiments 3, 4and 5 will be now described.

For an image forming apparatus 200 described in Embodiments 3, 4 and 5,a method for mounting and removing a cartridge P is different from thatfor the image forming apparatus 100 of Embodiments 1 and 2. InEmbodiments 3, 4 and 5, timings of cartridge pressing and exposure unitpressing are shifted to reduce a force required for pressing in theimage forming apparatus 200.

Embodiment 3

<General Configuration of Image Forming Apparatus 200>

A general configuration of the image forming apparatus 200 will bedescribed. The image forming apparatus 200 of this embodiment is anelectrophotographic color image forming apparatus. FIG. 19 is aschematic sectional view illustrating a general configuration of theimage forming apparatus 200.

In the image forming apparatus 200, a feed unit 280 is placed at thebottom. The feed unit 280 contains sheets as recording materials. Aregistration roller unit 250 that registers and conveys the sheets isplaced in an upper right of the feed unit 280. Four cartridges P (PY,PM, PC and PK) are placed above the feed unit 280. An LED unit 230described later is placed between the cartridges P, and exposes aphotosensitive drum 11. Above the cartridges P, an intermediate transferunit 240 is placed to face the cartridges P. The intermediate transferunit 240 includes an intermediate transfer belt 241. Inside theintermediate transfer belt 241, a primary transfer roller 242 (242Y,242M, 242C and 242K), an intermediate transfer belt driving roller 243,a secondary transfer facing roller 244, a tension roller 245 and anintermediate transfer belt cleaning unit 246 are provided. A secondarytransfer unit 290 is placed on a right side of the intermediate transferunit 240, and a secondary transfer roller 291 is provided to face thesecondary transfer facing roller 244. A fixing unit 220 is placed abovethe intermediate transfer unit 240 and the secondary transfer roller291. A paper discharge unit 260 is placed in an upper left of the fixingunit 220. The paper discharge unit 260 includes a pair of paperdischarge rollers 261 and a double-sided conveyor portion 262, a pair ofreverse rollers 263 and a double-sided flapper 264 as a branch unit.

<Configuration of Cartridge>

Next, a configuration of a cartridge that includes members for imageforming, can be mounted to and removed from the image forming apparatus200, and performs image forming while being mounted to the image formingapparatus 200 will be described. The cartridges P (PY, PM, PC and PK)are process cartridges each including a photosensitive drum 1 (1Y, 1M,1C and 1K) and a process unit that acts on the photosensitive drum. Fourcartridges P (PY, PM, PC and PK) can be mounted to and removed from themain body 200. The four cartridges P are different in forming tonerimages of different colors, and respectively contain toner of yellow(Y), magenta (M), cyan (C) and black (K). Since the four cartridges Phave the same structure other than the above, one cartridge P will bedescribed below as a representative. Members or the like included in thecartridge P will be also described as representatives.

FIG. 20 is a schematic sectional view of the cartridge P and therearoundin the image forming apparatus 200. In the cartridge P, a cleaner unit217 and a developing unit 214 are integrally configured.

The cleaner unit 217 includes a photosensitive drum 1, a charging roller212, a cleaning blade 2161 and a waste toner container 2162. Thephotosensitive drum 1 is formed by applying an organic photoconductorlayer (OPC) to an outer peripheral surface of an aluminum cylinder. Thephotosensitive drum 1 is rotatably supported by flanges at opposite endsin an axial direction, and is rotated by a drive force applied by adrive motor (not shown) in the main body 200.

A charging roller 212 is a conductive roller, and is abutted against thesurface of the photosensitive drum 1. In abutment, a charging biasvoltage is applied to uniformly charge the surface of the photosensitivedrum 1. Transfer residual toner remaining on the surface of thephotosensitive drum 1 after primary transfer is removed by a cleaningblade 2161. The removed toner is collected in the waste toner container2162.

The developing unit 214 includes a developing roller 2142, a tonersupply/recovery roller 2143 and a toner containing portion 2144. Thedeveloping roller 2142 that applies toner to an electrostatic latentimage and develops the image as a toner image is placed adjacent to thephotosensitive drum 1, rotated by the drive force of the drive motor(not shown) in the main body 200, and applies a development bias voltageto perform development of the photosensitive drum 1. The tonersupplying/collecting roller 2143 supplies toner from the tonercontaining portion 2144 to the developing roller 2142, and collectstoner that has not been used for development of the photosensitive drum1.

<Configuration of LED Unit 230>

A configuration of an LED unit 230 (230Y, 230M, 230C and 230K) will bedescribed.

The LED unit 230 is placed between the developing unit 214 and thecleaner unit 217 of each of the four cartridges P mounted to the mainbody 200, exposes the photosensitive drum 1 based on image information,and forms an electrostatic latent image on the photosensitive drum 1.Since the four LED units 230 (230Y, 230M, 230C and 230K) have the samestructure, one LED unit 230 will be described as a representative.Members or the like included in the LED unit 230 will be also describedas representatives.

The LED unit 230 includes an LED frame 231, an LED head 232 as anexposure member, a cartridge pressing member 235 (see FIG. 23) and apressing spring 236.

The LED head 232 include an LED array 233 in which a plurality of LEDlight emitting elements are arranged in an array in a main scanningdirection according to a predetermined pixel pitch, and a lens array 234through which light from each LED light emitting element of the LEDarray 233 passes, integrated into a unit. The LED array 233 emits lightbased on image data to be formed, applies light to the rotatingphotosensitive drum 1, and exposes the photosensitive drum 1. The LEDframe 231 includes the LED head 232, a cartridge pressing member 235 anda pressing spring 236.

The LED head 232 and the cartridge pressing member 235 are integrallyformed and urged to abut against the cartridge P in the image formingposition and thus positioned in the exposure position. Thus, the LEDhead 232 and the cartridge pressing member 235 are urged upward by thepressing spring 236, and supported by the LED frame 231 so as to befreely movable by a predetermined amount in the vertical direction (Zdirection) and the axial direction of the photosensitive drum 1 withrespect to the LED frame 231.

The LED unit 230 can be retracted from the cartridge so as not tointerfere with the movement of the cartridge P when the cartridge P ismounted to or removed from the main body 200. Specifically, the LED unit230 is supported by a cartridge guide 2100 movably in the verticaldirection (Z direction) via an LED unit push-up cam 2101 (see FIG. 23).

<Image Forming Operation>

A color image forming operation of the image forming apparatus 200 ofthis embodiment will be described. The image forming operation isperformed in a state where the cartridge P is mounted to the apparatusand located in the image forming position. As described above, thephotosensitive drum 1 is driven and rotated in an A direction (FIG. 20).In this state, the surface of the photosensitive drum 1 is uniformlycharged by the charging roller 212, and exposed by the LED unit 230, andthus an electrostatic latent image is formed on the surface. Thedeveloping roller 2142 applies toner to the electrostatic latent imageto form a toner image on the surface of the photosensitive drum 1. Atransfer bias is applied to the toner image in a position where thesurface of the photosensitive drum 1 faces the primary transfer roller242, and the toner image is transferred from the surface of thephotosensitive drum 1 onto the intermediate transfer belt 241.

The toner images are transferred in a superimposed manner to theintermediate transfer belt 241 in positions facing the photosensitivedrums (1Y, 1M, 1C and 1K), and the toner image as superimposed imagesincluding four color toner images are formed on the intermediatetransfer belt 241. The toner images are collectively transferred fromthe intermediate transfer belt 241 onto a sheet fed from the feed unit280 at the same timing in a position facing the secondary transferroller 244.

The sheet to which the toner image has been transferred is conveyed tothe fixing unit 220, where the toner image is fixed on the sheet byheating and pressurizing, and the sheet is discharged to the outside ofthe apparatus by the paper discharge unit 260. The image is formed onthe sheet by the above-described operation.

<Mounting of Cartridge P to Main Body>

Mounting of the cartridge P to the image forming apparatus 200 will bedescribed. FIG. 21 is a perspective view of the image forming apparatus200 when the cartridge P is mounted, seen obliquely from the front. Inthis embodiment, the cartridge P is moved in the rotating axis directionof the photosensitive drum 1 and inserted into or drawn from the mainbody 200, and thus can be mounted to or removed from the main body 200.The configuration of mounting and removing the cartridge P is referredto as a so-called side-oriented configuration.

When the cartridge P is mounted to the image forming apparatus 200, theopenable and closable member 270 is opened with respect to the main body200 to expose the opening portion 271. Four cartridge guides 2100(2100Y, 2100M, 2100C and 2100K) arranged in line in a directionperpendicular to the axis of the photosensitive drum 1 are exposed fromthe opening portion 271. The cartridge P is inserted in an F directionaccording to the cartridge guide 2100 so that the cartridge guide 2100is interposed between the cleaner unit 217 and the developing unit 214,and thus can be mounted to the main body 200. FIG. 21 illustrates astate where the cartridge PM has been already mounted to the main body200, and the cartridge PY is being inserted into the main body 200.

As described above, in the configuration in which the cartridge P isinserted into the main body 200 in the axial direction of thephotosensitive drum 1, and thus mounted to and removed from the mainbody 200, the photosensitive drum 1 may rub against a member such as theintermediate transfer belt 241 close to the photosensitive drum 1 in themain body 200 and damage each other in mounting and removal of thecartridge P. Thus, the cartridge P is inserted in a state where thecartridge P is retracted in a predetermined distance from theintermediate transfer belt 241 or the like in the directionperpendicular to the axis of the photosensitive drum 1.

In this embodiment, the intermediate transfer belt 241 is placed abovethe photosensitive drum 1, and thus when the cartridge P is inserted,the cartridge P is first retracted below the intermediate transfer belt241. Then, immediately before completion of the insertion of thecartridge P, the cartridge P is moved upward against the gravity, andreaches the image forming position where the photosensitive drum 1 isclose to the intermediate transfer belt 241.

In the configuration in which the cartridge P is pushed upward againstthe gravity in insertion, and thus moved in the direction perpendicularto the axis of the photosensitive drum 1, a larger pressing force isrequired than for moving the cartridge P in other directions.

As described above, in this embodiment, the LED unit 230 is movedupward, and the LED head 232 is pressed toward the cartridge P toposition the LED head 232 in the exposure position. Thus, if the timingof pushing the cartridge P upward is always the same as the timing ofmoving the LED unit 230 upward, reaction forces applied to the user inmounting the cartridge P simultaneously reach the peak, therebyincreasing a load on the user.

Thus, in this embodiment, the timings of the reaction forces applied tothe user in mounting the cartridge P are shifted.

A configuration for moving the cartridge P upward and positioning thecartridge P in the main body 200 will be described in detail.

FIG. 22 is a schematic perspective view of the cartridge P andtherearound in the image forming apparatus 200. The cartridge P is shownbeing inserted. In the apparatus, the front plate 2110 and the rearplate 2120 are placed at opposite ends in the axial direction (Fdirection) of the photosensitive drum 1 with the cartridge P beingmounted to the apparatus. At opposite ends in the axial direction of thephotosensitive drum 1 of the cartridge P, positioned portions 213 a and213 b are provided for positioning the photosensitive drum 1 in the mainbody 200.

The front plate 2110 includes a pull-up member 2111 as a first movingmember that is pushed down by a pulled-up portion 2113 of the cartridgeP and then pulls up the pulled-up portion 2113 immediately beforecompletion of insertion of the cartridge P. The pull-up member 2111 isprovided rotatably around a shaft 2118, and urged upward (Z direction)by a pull-up spring 2116 hung on a hanging portion 2117 on the frontplate 2110. The front plate 2110 has abutment portions 2112 a and 2112b.

The rear plate 2120 includes a push-up member 2121 as a first movingmember that is pushed down by a pushed-up portion 2123 of the cartridgeP and then pushes up the pushed-up portion 2123 immediately beforecompletion of insertion of the cartridge P. The push-up member 2121 isprovided rotatably around a shaft 2128, and urged upward (Z direction)by a push-up spring 2126. The rear plate 2120 has abutment portions 2122a and 2122 b.

The cartridge P is moved upward by the pull-up member 2111 and thepush-up member 2121 in insertion into the main body 200.

A configuration will be described of mounting the cartridge P to themain body 200 and positioning the cartridge P in the image formingposition, and positioning the LED unit 230 and the LED head 232 on thecartridge P.

FIG. 23 is a partial sectional view of the image forming apparatus 200in mounting and removing the cartridge P. This section includes the axisof the photosensitive drum 1 and is parallel to the Z direction.

In this state, the LED unit 230 including the LED head 232 is located ina retracted position retracted downward with respect to thephotosensitive drum 1 of the cartridge P.

In this state, the cartridge P is inserted into the main body 200 in theaxial direction (F direction) of the photosensitive drum 1. As shown inFIG. 24, the pulled-up portion 2113 of the cartridge P first abutsagainst the pull-up member 2111 to rotate the pull-up member 2111downward around the shaft 2118 (FIG. 22). At the same time, thepushed-up portion 2123 of the cartridge P abuts against the push-upmember 2121 to rotate the push-up member 2121 downward around the shaft2128 (FIG. 22).

When the cartridge P is further inserted in the F direction, as shown inFIG. 25, the pulled-up portion 2113 rides on a pull-up surface 2114 ofthe pull-up member 2111. At the same time, the pushed-up portion 2123also rides on the push-up member 2121. As such, the cartridge P pressesthe pull-up member 2111 and the push-up member 2121, and rides thereon.Thus, biasing forces of the pull-up spring 2116 of the pull-up member2111 and the push-up spring 2126 of the push-up member 2121 move thecartridge P upward by a predetermined amount.

Further, at this time, a cam abutment surface 2103 provided on thecartridge P abuts against a cartridge abutment surface 2102 provided inan LED unit push-up cam 2101 as a second moving member.

When the cartridge P is further inserted in the F direction in thisstate, as shown in FIG. 26, the LED unit push-up cam 2101 is pressed bythe cartridge P and moved in the F direction. The cam surface 2104 forpushing up the LED unit 230 of the LED unit push-up cam 2101 abutsagainst the cam surface 2105 of the LED unit 230, and the LED unit 230is pushed up upward (Z direction) toward the photosensitive drum 1.

The LED unit 230 is pushed up, and thus the cartridge push-up member 235urged upward by the pressing spring 236 of the LED unit 230 abutsagainst the cartridge P to press the cartridge P. This further moves thecartridge P upward.

As shown in FIG. 27, the positioned portions 213 a and 213 b abutagainst the abutment portions 2112 a and 2112 b of the front plate 2110and the abutment portions 2122 a and 2122 b of the rear plate 2120. Thisdetermines the position of the cartridge P in the vertical direction (Zdirection) and the direction vertically perpendicular to the cartridgeinsertion direction (F direction).

At the same time, a part of the cartridge P abuts against the rear plate2120 in the cartridge insertion direction (F direction) to determine theposition in the cartridge insertion direction (F direction).

As described above, the cartridge P reaches the image forming positionand is positioned. The cartridge pressing member 235 fits in the fittinghole 2106 of the cartridge P to position the LED head 232 of the LEDunit 230 in the main scanning direction (F direction) and a sub scanningdirection (direction perpendicular to the F and Z directions) of thecartridge P. As such, the LED head 232 reaches the exposure position andis positioned.

A resultant force of pressing forces of the pull-up member 2111, thepush-up member 2121 and the cartridge pressing member 235 of the LEDunit 230 causes a sufficient pressing force to position the cartridge Pin the image forming position and transfer the toner image to theintermediate transfer belt 241.

In this embodiment, the cartridge P rides on the pull-up member 2111 andthe push-up member 2121 to move the cartridge P upward by apredetermined amount. However, at this time, the cartridge P does notabut against the abutment portions 2112 a and 2112 b and the abutmentportions 2122 a and 2122 b. This is for preventing the cartridge P frombeing brought into contact with and rubbing against the front plate2110, the rear plate 2120, or the intermediate transfer unit 240 placedabove the cartridge P when the cartridge P is then further inserted tomove the LED unit 230 upward.

If an insertion distance of the cartridge P for moving the LED unit 230upward is relatively short, the cartridge P may ride on the pull-upmember 2111 and the push-up member 2121 so that the cartridge P abutsagainst the abutment portions 2112 a and 2112 b and the abutmentportions 2122 a and 2122 b.

<Removal of Cartridge P from Main Body>

Next, drawing and removing the cartridge P from the main body 200 willbe described. As shown in FIG. 27, with the cartridge P being completelyinserted into the main body, an engaging portion 2107 of the cartridge Pengages an engaging portion 2108 of the LED unit push-up cam 2101. Thus,when the cartridge P is drawn in a direction opposite to the F directionfrom the state shown in FIG. 27, the LED unit push-up cam 2101 is alsomoved in the direction opposite to the F direction. At this time, thecam surface 2105 slides on the cam surface 2104 of the LED unit push-upcam 2101 to move the LED unit 230 downward. Thus, the cartridge pressingmember 235 is withdrawn from the fitting hole 2106 of the cartridge P,and the LED head 232 is moved from the exposure position to theretracted position. At the same time, the cartridge P is moved downwardby a predetermined amount and retracted from the image forming position,and enters a state as shown in FIG. 25.

In this state, the engaging portion 2107 of the cartridge P isdisengaged from the engaging portion 2108 of the LED unit push-up cam2101. Thus, the cartridge P can be further drawn in the directionopposite to the F direction. When the cartridge P is further drawn inthe direction opposite to the F direction, the cartridge P is withdrawnfrom the pull-up member 2111 and the push-up member 2121, moved downwardby a predetermined amount, and can be removed from the main body.

<Operation Force in Insertion of Cartridge P into Main Body 200>

An operation force required for inserting the cartridge P into the mainbody 200, positioning the cartridge P in the image forming position, andpositioning the LED head 232 in the exposure position will be described.

FIG. 28A is a graph illustrating an operation force required when thecartridge P presses the pull-up member 2111 and the push-up member 2121in insertion of the cartridge P. The operation force increases betweenwhen the cartridge P presses the pull-up member 2111 and the push-upmembers 2121 and when the cartridge P pushes down and rides on themembers. The operation force reaches a peak (maximum value) when thepull-up spring 2116 extends to the maximum and the push-up spring 2126contracts to the minimum.

The operation force may be restated as a reaction force applied to thecartridge P when the cartridge P presses the pull-up member 2111 and thepush-up member 2121 against the biasing forces of the pull-up spring2116 and the push-up spring 2126. FIG. 28B is a graph illustrating anoperation force when the cartridge P presses the LED push-up cam 2101 ininsertion of the cartridge P. The operation force increases while thecam surface 2104 of the LED push-up cam 2101 pressed and moved by thecartridge P is pushing up the cam surface 2105 of the LED unit 230. Theoperation force reaches a peak (maximum value) when the pressing spring236 of the LED unit 230 contracts to the minimum.

The operation force may be restated as a reaction force applied to thecartridge P when the cartridge P presses the LED unit push-up cam 2101against the biasing force of the pressing spring 236 of the LED unit230.

As such, in insertion of the cartridge P, the operation force reachesthe peak when the pull-up member 2111 and the push-up member 2121 arepressed and when the LED push-up cam 2101 is pressed.

FIG. 28C is a graph illustrating an operation force in insertion of thecartridge P. The operation force reaches [α] while the cartridge P ispressing the pull-up member 2111 and the push-up member 2121, andreaches [β] while the cam surface 2104 of the LED push-up cam 2101pressed and moved by the cartridge P is pushing up the cam surface 2105of the LED unit 230. As such, in this embodiment, the timing when thecartridge P presses the pull-up member 2111 and the push-up member 2121is different from the timing when the cartridge P presses the LEDpush-up cam 2101 in insertion of the cartridge P. Thus, the timings ofthe peak of the operation force in insertion of the cartridge areshifted (made different).

Specifically, in this embodiment, the cartridge P is moved upward by thepredetermined amount, and then the LED unit 230 is moved upward, and thecartridge P is moved upward in a plurality of separate times to reachthe image forming position. Thus, as compared to a configuration inwhich the cartridge P is moved upward once at the same timing as upwardmovement of the LED unit 230 and moved to the image forming position,the maximum value of the operation force required in insertion of thecartridge can be reduced to improve usability.

Embodiment 4

Next, Embodiment 4 will be described. In Embodiment 3, the cartridge Pis positioned in the image forming position in conjunction with theinsertion of the cartridge P, and the LED unit 230 is pushed upward. Incontrast to this, in this embodiment, a cartridge P is positioned in animage forming position in conjunction with insertion of the cartridge P,an LED unit 230 is moved in conjunction with a closing operation of anopenable and closable member 270 for inserting the cartridge P, and anLED head 232 is moved to an exposure position.

In the description of this embodiment, the same components as inEmbodiment 3 are denoted by the same reference numerals and descriptionsthereof will be omitted, and different points will be described.

<Mounting of Cartridge P to Main Body>

A mounting operation when the cartridge P is mounted to an image formingapparatus 200 in this embodiment will be described.

FIG. 29 is a perspective view of the image forming apparatus 200 seenobliquely from the front. The image forming apparatus 200 includes aninner openable and closable member 272 openable and closable withrespect to a main body inside an openable and closable member 270. Theinner openable and closable member 272 is opened/closed in conjunctionwith the openable and closable member 270, and the openable and closablemember 270 and the inner openable and closable member 272 are opened toopen the opening portion 271. In replacement of the cartridge P, theopenable and closable member 270 and the inner openable and closablemember 272 are opened to open the opening portion 271. The openingportion 271 is opened to expose four cartridge guides 2100 arranged inparallel in the main body.

The cartridge P is inserted along the cartridge guides 2100 into themain body 200 in an axial direction (F direction) of a photosensitivedrum 1. As in Embodiment 3, a pulled-up portion 2113 of the cartridge Pabuts against a pull-up member 2111 to rotate the pull-up member 2111downward around a shaft 2118. At the same time, a pushed-up portion 2123of the cartridge P abuts against a push-up member 2121 to rotate thepush-up member 2121 downward around a shaft 2128.

When the cartridge P is further inserted in the F direction, as shown inFIG. 30, the pulled-up portion 2113 rides on the pull-up surface 2114 ofthe pull-up member 2111. At the same time, the pushed-up portion 2123also rides on the push-up member 2121. As such, the cartridge P pressesand rides on the pull-up member 2111 and the push-up member 2121. Thus,the cartridge P is moved upward by biasing forces of a pull-up spring2116 of the pull-up member 2111 and a push-up spring 2126 of the push-upmember 2121.

Then, as shown in FIG. 30, positioned portions 213 a and 213 b abutagainst abutment portion 2112 a and 2112 b of a front plate 2110 andabutment portions 2122 a and 2122 b of a rear plate 2120. Thus, theposition of the cartridge P is determined in a vertical direction (Zdirection) and a direction vertically perpendicular to a cartridgeinsertion direction (F direction) (see FIG. 22).

At the same time, a part of the cartridge P abuts against the rear plate2120 in the cartridge insertion direction (F direction) to determine theposition of the cartridge P in the cartridge insertion direction (Fdirection).

As described above, the cartridge P reaches and is positioned in theimage forming position.

The inner openable and closable member 272 includes a cam pressingportion 2203 that abuts against and presses a pressed surface 2202 of anLED unit push-up cam 2101. An engaging portion 2230 is provided at a tipof the cam pressing portion 2203.

FIGS. 32A and 32B illustrate a part of the image forming apparatus 200around the inner openable and closable member 272 and the cartridgeguide 2100 seen from above. When the openable and closable member 270 isclosed, as shown in FIG. 32A, an engaging portion 2230 of the campressing portion 2203 of the inner openable and closable member 272engages an inner openable and closable member engaging portion 2231 ofthe LED unit push-up cam 2101.

When the openable and closable member 270 is further closed, as shown inFIG. 32B, the cam pressing portion 2203 abuts against the pressedsurface 2202 to move the LED unit push-up cam 2101 in the F direction.

As described above, the LED unit push-up cam 2101 is moved in the Fdirection, and thus as in the first embodiment, the LED unit 230 ismoved upward, and a cartridge push-up member 235 fits in a fitting hole2106 in the cartridge P. Thus, as shown in FIG. 31, an LED head 232 ispositioned in the exposure position.

When the cartridge P is removed from the main body 200, the openable andclosable member 270 is opened to open the inner openable and closablemember 272. At this time, the LED unit push-up cam 2101 including theinner openable and closable member engaging portion 2231 that engagesthe engaging portion 2230 of the cam pressing portion 2203 of the inneropenable and closable member 272 is moved in the direction opposite tothe F direction in conjunction with the operation of opening the inneropenable and closable member 272. The LED unit 230 is moved downward tomove the LED head 232 from the exposure position to the retractedposition as in Embodiment 3. The cartridge P is drawn in the directionopposite to the F direction in this state, and thus the cartridge P canbe removed from the main body 200.

<Operation Force in Mounting the Cartridge P to the Main Body 200>

Next, an operation force required for inserting the cartridge P into themain body 200 to close the openable and closable member 270, positioningthe cartridge P in the image forming position, and positioning the LEDhead 232 in the exposure position.

The operation force required in insertion of the cartridge P reaches apeak between when the cartridge P presses the pull-up member 2111 andthe push-up member 2121 and when the cartridge P pushes down and rideson the members. The operation force required for closing the openableand closable member 270 reaches a peak while the cam pressing portion2203 is pressing the pressed surface 2202 to move the LED unit push-upcam 2101 in the F direction, and the cam surface 2104 is pushing up thecam surface 2105 of the LED unit 230.

Thus, in this embodiment, the cartridge P is moved upward to the imageforming position in conjunction with insertion of the cartridge P, andthen the LED unit 230 is moved upward in conjunction with closing theopenable and closable member 270 to move the LED head 232 to theexposure position. Thus, as compared to a configuration in which thecartridge P is moved upward once at the same timing as upward movementof the LED unit 230 and positioned in the image forming position, themaximum value of the required operation force can be reduced. Thisreduces an operation force required for mounting the cartridge P toimprove usability.

Embodiment 5

Next, Embodiment 5 will be described. This embodiment is different fromEmbodiment 3 in that a guide member 251 that guides insertion of acartridge P can be drawn from a main body 200 according to mounting andremoval of the cartridge P. In this embodiment, a case where the guidemember 251 is configured to be drawable as a cartridge placement memberon which the cartridge P is placed is described.

In the description of this embodiment, the same components as inEmbodiment 3 are denoted by the same reference numerals and descriptionsthereof will be omitted, and different points will be described.

<Drawing Configuration of Guide Member 251>

A drawing configuration of the guide member 251 will be described. FIG.33 is a sectional view of the cartridge P and therearound in the imageforming apparatus 200 of this embodiment seen in an axial direction of aphotosensitive drum 1. FIG. 34 is a partial perspective view of theimage forming apparatus 200 in a state where the cartridge P is placedon the guide member 251 drawn from the main body. An exterior portion ofthe image forming apparatus 200 is not shown.

The guide member 251 is a thin plate member that is long in a front/reardirection and protrudes upward, and is provided along a rail 220 aprovided on an upper surface frame 220 corresponding to a rail groove251 c so as to be movable in the axial direction of the photosensitivedrum 1. The guide member 251 includes a lateral direction restrictionwall (region that can abut against the cartridge P) 258 that guides thecartridge P in the left and right direction, and a vertical directionrestriction wall 259 that guides the cartridge P in a verticaldirection. The vertical direction restriction wall 259 is provided onboth left and right sides of the guide member 251 in the axial direction(longitudinal direction of the guide member 251) of the photosensitivedrum 1. On the side of an opening portion 271 (front side) of the guidemember 251, a grip 264 (FIG. 35) gripped by a user for drawing the guidemember 251 toward the opening portion 271 is provided.

The LED unit 230 is placed inside the guide member 251. The LED unit 230is held by an LED holding rail 251 d formed inside the guide member 251,and an LED holding casing 2154 secured to an upper surface frame 220.The LED unit 230 is not drawn but is secured and held in the main body200 even if the guide member 251 is drawn.

FIG. 35 is a sectional view taken in the axial direction of thephotosensitive drum 1. In this embodiment, an LED unit push-up mechanism2150 including a push-up cam 2153 is provided as a mechanism forvertically moving the LED unit 230 and moving an LED head 232 betweenthe retracted position and the exposure position. Two LED unit push-upmechanisms 2150 are provided apart from each other in the axialdirection of the photosensitive drum 1.

The LED unit push-up mechanism 2150 will be described. Two push-up cams2153 are provided in one LED unit 230, one on an upstream side and theother on a downstream side in the F direction. The push-up cam 2153 isheld rotatably in the arrow E direction by a cam holding member 2151secured to the upper surface frame 220. A toggle spring 2152 extendsbetween the push-up cam 2153 and the cam holding member 2151. One end ofthe toggle spring 2152 is supported by an extending portion 2151 a ofthe cam holding member 2151. The other end is supported by an extendingportion 2153 a provided below the push-up cam 2153. With such aconfiguration, the push-up cam 2153 serves as a toggle mechanism.

<Mounting of Cartridge P to Main Body>

Mounting of the cartridge P to the image forming apparatus 200 will bedescribed. In mounting the cartridge, the guide member 251 correspondingto the cartridge P to be mounted is drawn toward the opening portion 271(front side). In this state, the cartridge P is placed on the guidemember 251 so that the guide member 251 enters a space between a cleanerunit 217 and a developing unit 214 of the cartridge P. In this state,the vertical direction restriction wall 259 is brought into contact witha bottom surface of the cartridge P.

With the guide member 251 being drawn toward the opening portion 271,the guide member 251 is secured in a state of being urged in a drawingdirection from the main body 200 by a toggle mechanism (not shown).Thus, even if the cartridge is inserted in the F direction, the guidemember 251 is held in a state of being drawn toward the opening portion271 against a friction force between the cartridge P and the guidemember 251, and only the cartridge P slides on the guide member 251 andis moved in the F direction. At this time, a slope portion 258 a (FIG.34) is longitudinally formed on left and right sides of an upper portionof the guide member 251 so as to facilitate insertion of the cartridgeP.

When the cartridge P is inserted so that an abutment surface 266 of thecartridge P abuts against an abutment surface 265 of the guide member251, the abutment surface 266 of the cartridge P presses the abutmentsurface 265 of the guide member 251. This releases urging of the guidemember 251 of the toggle mechanism in a drawing direction from the mainbody 200. Thus, the cartridge P and the guide member 251 are thenintegrally inserted into the main body in the F direction.

As shown in FIG. 36A, the pulled-up portion 2113 provided in thecartridge P abuts against the pull-up member 2111. At the same time, thepushed-up portion 2123 of the cartridge P abuts against the push-upmember 2121. As shown in FIG. 36B, when the cartridge P is pressed inthe F direction as in Embodiment 3, the cartridge P rides on the pull-upmember 2111 and the push-up member 2121 and is moved in the Z directionby a predetermined amount. At this time, as in Embodiment 3, thecartridge P has not abut against the abutment portions 2112 a and 2112 band the abutment portions 2122 a and 2122 b. In this state, the cam 2153is urged by the toggle spring 2152 so as to be rotated in an arrow Ddirection.

In FIGS. 36A to 36D, the push-up member 2121 of the rear plate 2120 isnot shown. The push-up cam 2153 on the downstream side in the Fdirection operates in the same manner as that on the upstream side inthe F direction, and thus illustration and descriptions thereof will beomitted.

Further, when the cartridge P is inserted in the F direction, as shownin FIG. 36B, the cam abutment surface 251 a provided on the guide member251 abuts against the push-up cam 2153. The abutment surface 251 a ismoved with the movement of the guide 251 in the F direction, the push-upcam 2153 is pressed, and the push-up cam 2153 is rotated in the arrow Cdirection against the biasing force of the toggle spring 2152. At thistime, the cam surface 2153 b provided on the push-up cam 2153 presses abottom surface of the LED unit 230, and moves the LED unit 230 upward.

When the cartridge P is further inserted, as shown in FIG. 36C, theextending portion 2153 a of the toggle spring 2152 reaches a neutralposition shown by the dash-single-dot line. When the extending portion2153 a goes beyond the neutral position, the toggle spring 2152 urgesthe push-up cam 2153 in the arrow C direction, the push-up cam 2153 isfurther rotated in the arrow C direction, and the LED unit 230 isfurther moved upward. As shown in FIG. 36D, the cartridge P is pressedby the cartridge push-up member 235 provided on the LED unit 230 andmoved upward, and the positioned portions 213 a and 213 b abut againstthe abutment portions 2112 a and 2112 b of the front plate 2110, and theabutment portions 2122 a and 2122 b of the rear plate 2120. Thus, thecartridge P is positioned in the vertical direction (Z direction) andthe direction vertically perpendicular to the cartridge insertiondirection (F direction).

The guide member 251 pressed by the cartridge P abuts against a stopperportion (not shown) provided on a side plate 2120 in the F direction toprevent the cartridge P and the guide member 251 from being furtherinserted and moved. At this time, the push-up cam 2153 abuts against theLED unit 230 at a portion vertically upward of a rotation center of thepush-up cam 2153, and is arranged in the vertical direction. Thus, thereaction force to rotate the push-up cam 2153 is directed to therotation center of the push-up cam 2153 by self-weight or the like ofthe LED unit 230, and thus the push-up cam 2153 is not rotated and heldin this state.

At the same time, the cartridge pressing member 235 fits in the fittinghole (not shown) in the cartridge P to position the LED head 232 in themain scanning direction (F direction) and the sub scan direction(direction perpendicular to the F and Z directions) of the cartridge P.As such, the LED head 232 reaches the exposure position and ispositioned. The LED head 232 is positioned in the exposure position, andthus the cartridge P reaches the image forming position and ispositioned.

A resultant force of pressing forces of the pull-up member 2111, thepush-up member 2121 and the cartridge pressing member 235 of the LEDunit 230 causes a sufficient pressing force to position the cartridge Pin the image forming position and transfer the toner image to theintermediate transfer belt 241.

<Removal of Cartridge P from Main Body>

Drawing and removing the cartridge P from the main body 200 will bedescribed. As shown in FIG. 36D, with the cartridge P being mounted tothe main body 200 and being in the image forming position, the grip 264is held to draw the guide member 251 in the direction opposite to the Fdirection. Then, the cam abutment surface 251 b provided on the guidemember 251 abuts against the push-up cam 2153 to rotate the push-up cam2153 in the arrow D direction. At this time, the LED unit 230 is moveddown along the cam surface 2153 b. Thus, the cartridge pressing member235 is withdrawn from the fitting hole in the cartridge P, and the LEDhead 232 is moved from the exposure position to the retracted position.At the same time, the cartridge P is also moved downward by apredetermined amount and retracted from the image forming position.

When the guide member 251 is further drawn, as shown in FIG. 36C, theextending portion 2153 a of the toggle spring 2152 goes beyond a neutralposition of the toggle mechanism, and the push-up cam 2153 is urged inthe arrow D direction by the toggle spring 2152. Then, when the guidemember 251 is drawn to the position shown in FIG. 36B, rotation of thepush-up cam 2153 is restricted by a detent (not shown).

When the guide member 251 is further drawn, the abutment surface 266 ispressed against the abutment surface 265 of the guide member 251, thecartridge P drawn integrally with the guide member 251 is disengagedfrom the pull-up member 2111 and the push-up member 2121, and moveddownward by a predetermined amount. As such, the guide member 251 isdrawn toward the opening portion 271 to draw the cartridge P, and thusthe cartridge P can be removed from the main body 200.

As such, in this embodiment, as in Embodiment 3, the timing when thecartridge P presses the pull-up member 2111 and the push-up member 2121is different from the timing when the cartridge P presses the push-upcam 2153 in insertion of the cartridge P. Thus, the timings of the peakof the operation forces in insertion of the cartridge are shifted.

Specifically, in this embodiment, the cartridge P is moved upward by apredetermined amount, and then the LED unit 230 is moved upward, and thecartridge P is moved upward in a plurality of separate times to reachthe image forming position. Thus, as compared to a configuration inwhich the cartridge P is moved upward once at the same timing as upwardmovement of the LED unit 230 and moved to the image forming position,the maximum value of the operation force required in insertion of thecartridge can be reduced to improve usability.

In this embodiment, with the guide member 251 being drawn from the mainbody 200 toward the opening 271, the center of gravity of the cartridgeP is placed outside of the main body 200 in the longitudinal direction(axial direction of the photosensitive drum 1) of the cartridge P.

Thus, the user can grip a portion corresponding to the center of gravityof the cartridge P in the longitudinal direction of the cartridge P.Thus, as compared to a case where the user grips an end of the cartridgeP in the longitudinal direction to insert or remove the cartridge P intoor from the main body 200, the cartridge can be held and operatedwithout application of the moment of the center of gravity of thecartridge P for good usability.

<Other Embodiments>

In Embodiments 4 and 5, the replacement of cartridge P having aside-oriented configuration in which the cartridge P is inserted intothe axial direction of the photosensitive drum 1 and thus mounted to orremoved from the main body 200 has been described. However, thecartridge P may be applied to a configuration in which the cartridge Pis drawn in a direction different from an arrangement direction of thecartridge P and the LED unit 230 and a direction perpendicular to theaxial direction of the photosensitive drum 1 (for example, JapanesePatent Application Laid-Open No. 2009-128506).

Also in such a configuration, in mounting and removal of the cartridgeP, the cartridge P and the LED unit 230 are moved in the arrangementdirection of the cartridge P and the LED unit 230. Thus, in thisconfiguration, timing when the cartridge P is moved in the arrangementdirection of the cartridge P and the LED unit 230 is different fromtiming when the LED unit 230 is moved in the arrangement direction ofthe cartridge P and the LED unit 230. Such a configuration can reduce amaximum value of a required operation force.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2010-126812, filed Jun. 2, 2010, Japanese Patent Application No.2011-114806, filed May 23, 2011 and Japanese Patent Application No.2011-091240, filed Apr. 15, 2011, which are hereby incorporated byreference herein in their entirety.

What is claimed is:
 1. An image forming apparatus in which a cartridgethat supports a photosensitive member is mounted to an image formingposition, and which forms a latent image on the photosensitive member byexposure to form an image, the apparatus comprising: an exposure memberthat (i) includes a light emitting element arranged in an array and (ii)exposes the photosensitive member of the cartridge located in the imageforming position when the exposure member is in an exposure position; anoperation member that moves to a first position and a second positionwith respect to a main body of the apparatus; a first moving member thatis pressed and moved by the operation member when the operation memberis moved from the first position to the second position, and switchesthe cartridge from a state where the cartridge is positioned in theimage forming position to a state where the positioning is released; anda second moving member that is pressed and moved by the operation memberwhen the operation member is moved from the first position to the secondposition, and moves the exposure member from the exposure position to aretracted position where the exposure member is more retracted from thephotosensitive member than the exposure position, wherein, while theoperation member is moved from the first position to the second positionto switch the cartridge from the state where the cartridge is positionedto the state where the positioning is released, a first force acts fromthe first moving member to the operation member in a direction in whichthe moving of the operation member from the first position to the secondposition is suppressed, and wherein, while the operation member is movedfrom the first position to the second position to move the exposuremember from the exposure position to the retracted position, a secondforce acts from the second moving member to the operation member in adirection in which the moving of the operation member from the firstposition to the second position is suppressed, and wherein, while theoperation member is moved from the first position to the secondposition, timing of a peak of the first force is different from timingof a peak of the second force.
 2. The image forming apparatus accordingto claim 1, wherein, as the operation member is moved from the firstposition to the second position, the operation member presses and movesthe second moving member and then presses and moves the first movingmember.
 3. The image forming apparatus according to claim 1, wherein thefirst moving member is pressed and moved by the operation member toposition the cartridge in the image forming position when the operationmember is moved from the second position to the first position, whereinthe second moving member is pressed and moved by the operation member tomove the exposure member from the retracted position to the exposureposition when the operation member is moved from the second position tothe first position, and wherein timing when the operation member pressesthe first moving member to position the cartridge in the image formingposition is different from timing when the operation member presses thesecond moving member to move the exposure member to the exposureposition.
 4. The image forming apparatus according to claim 3, whereinthe first moving member and the second moving member are moved by atoggle mechanism.
 5. The image forming apparatus according to claim 1,wherein the operation member is an openable and closable member that canbe open or closed with respect to the main body of the apparatus,wherein the openable and closable member is closed with respect to themain body of the apparatus when the openable and closable member is inthe first position, and wherein the openable and closable member is moreopen with respect to the main body of the apparatus when the openableand closable member is in the second position than in the first positionso that the cartridge can be mounted to the main body of the apparatus.6. An image forming apparatus in which a cartridge that supports aphotosensitive member is inserted into a main body of the apparatus inan insertion direction along a longitudinal direction of the cartridgeand mounted to an image forming position inside the main body of theapparatus, and which forms a latent image on the photosensitive memberby exposure to form an image, the apparatus comprising: an exposuremember that (i) includes a plurality of light emitting elements arrangedin an array and (ii) exposes the photosensitive member of the cartridgelocated in the image forming position by the plurality of light emittingelements when the exposure member is in an exposure position, theexposure member being movable to a retracted position where the exposuremember is more retracted from the photosensitive member than theexposure position; an operation member that moves to a first positionand a second position with respect to the main body of the apparatus; afirst moving member that moves the cartridge to the image formingposition by moving the cartridge in a direction different from theinsertion direction when the cartridge is mounted to the main body ofthe apparatus; and a second moving member that moves the exposure memberfrom the retracted position to the exposure position as the operationmember is moved from the second position to the first position.
 7. Theimage forming apparatus according to claim 6, wherein the operationmember is an openable and closable member that can be open or closedwith respect to the main body of the apparatus, wherein the openable andclosable member is closed with respect to the main body of the apparatuswhen the openable and closable member is in the first position, andwherein the openable and closable member is more open with respect tothe main body of the apparatus when the openable and closable member isin the second position than in the first position so that the cartridgecan be mounted to the main body of the apparatus.
 8. The image formingapparatus according to claim 6, wherein the exposure member is withinthe main body of the apparatus when the exposure member is in theretracted position.